Loop antenna



Oct. 15, 1940. H. K'MORGAN 2,217,989

LOOP ANTEI-INA Filed May 5, 1937 INVENTOR. Hon 4rd /f. Marga/7 BY ,L/L.

ATTORNEYS Patented Oct. 15, 1940 UNETED STATES TENT FFEQE.

LOOP ANTENNA HowardK. MorgainKansas City, Mo., assignor toTranscontinental & Western Air, Inc., Kansas City, Mo., a corporationApplication May 3, 1937, Serial No. 140,465

9 Claims.

inexpensive to manufacture, easy to assemble,

and rugged in character when in use.

A yet further object of the instant'invention is to provide a loopantenna of theaforementioned type, having as a part thereof, meanswhereby the inductance coil may be looped within the tubular,ring-shaped casing without encountering the heretofore troublesomeproblems which presented themselves during the manufacture of suchequipment.

The specific embodiment of the broader concepts of this invention willbe detailed during the course of the following specification, referringto the accompanying drawing, wherein:

Figure 1 is a side elevation of a loop antenna made in accordance withthis invention, mounted as in use and diagrammatically associated withother parts of the radio system.

Fig. 2 is an enlarged, central, sectional view through the loop antennaper se.

Fig. 3 is an edge elevation of the same, with the outer element of atwo-part supporting fixture removed.

Fig. 4 is a cross sectional view through the loop antenna, taken on lineIVIV of Fig. 2', and,

Fig. 5 is a similar sectional View, taken along line VV of Fig. 2.

It has been found that a loop antenna constructed generally asillustrated herewith serves both the purpose of eliminating rain staticand providing a direction and position finding device. The loop antennaitself, broadly indicated by the numeral 8, is mounted beneath thefuselage It of the airplane in such manner as to permit its beingrotated by the pilot from a place in the pilots compartment and throughthe medium of a position indicator i2 that is equipped with a manuallyoperable crank 14. Position indicator I2 is operably joined to rotatingmechanism It through the medium of a torque control cable [8. A bracket2!], rigidly joined to some of the longitudinal stringers 22 of fuselage10, carries rotating mechanism It. The conventional radio receiver 24 isjoined to rotating mechanism [6 by insulated conductors 26, and uponmanipulation of crank l4, loop 8 and pointer 29 will be simultanecuslyactuated.

The manner of employing all of the aforementioned parts of the radiosystem diagrammatically illustrated is well known to those skilled inthe art, and since the specific manner of constructing loop 8 forms theimportant part of this invention, reference may be had to Figs. 2 to 5for an understanding of one illustrated embodiment.

A tubular ring-shaped casing 28 is initially a straight length of metalpipe, preferably aluminum, which is formed in any suitable manner so asto bring the ends 30 of the pipe into close proximity so that a tubularspacer 32 of insulating material may be positioned therebetween to breakthe continuity of the otherwise all metallic housing for the hereinaftermentioned inductance coil.

An opening 34 is provided through the wall of casing 28 for the passageof connections 36 which extend to radio receiver 24. After ring-shapedcasing 28 has been formed, a resilient, preferably flat band 38 isthreaded therethrough and its ends joined together by a link 49] ofinsulating material. This band 38 has a width less than the diameter ofcasing 28 so that its edges bear upon the inner face of casing 28, asshown in Fig. 4. After band 38 has been placed Within casing 23, endsare moved close together so as to diminish the diameter of casing 28,whereby band 38 may be rotated within the casing and about its axis. Thelooseness of fit between band 38 and casing 28 is maintained during theassembling operation, and thereafter ends 30 of band 38 are moved apartto receive spacer 32 vand to increase the frictional relation betweenthe edges of band 38 and the inner surface of casing 28. Thus band 38 issecured against relative displacement when the loop is in use.Obviously, spacer 32 must be first made of two or more sections so as topermit its being placed after band 38 has been made as just set down.

As band 38 is somewhat loosely and rotatably housed within casing 28,the antenna inductance coil is wound thereon. This inductance coil ismade of insulated wire 42 and is carried by a series of blocks 44 thatare on band 38. These blocks 44 are sectional so as to provide openings46 for the reception of wire 42. In the preferred embodiment, sections48 are formed as illustrated in Figs. 4 and 5, and the openings arenotches created inwardly from one edge of each section 48. U-shapedclips 50 extend through perforations 52 provided in band 38 and radiallyoutwardly extending legs of clips 50 pass through holes formed in eachsection 43 adjacent each end respectively thereof.

Sections 48 are progressively moved to position as wire 42 is loopedaround and over the sections already in place, and when the desiredamount of wire 42 has been fed into casing 28 by rotating band 38 andall of the blocks 44 carried thereby, the ends 54 of clips 50 are headedso as to hold sections 48 in place. Fig. 2 of the drawing teaches thatthere is a series of blocks 44 arranged in spaced relation around band38. The ends of wire 42 form the connections and through theconstruction just recited, no splicing of wire 42 occurs. The desirednumber of turns of wire 42 may be introduced into casing 28 upon blocks44, and after the inductance coil is thus completed, spacer 32 isinserted and the twopart fixture placed around casing 28 over opening34. This two-part fixture comprises a plate 56 and a co-operating neckelement 58, the bore whereof is in communication with opening 34 and theinterior of casing 28. Thus loop 8 may be rotatably mounted on therotating mechanism [6 and connections 36 joined to conductors leadingfrom radio receiver 24.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. A loop antenna for direction finding radio systems comprising alooped housing having a unitary tubular, ring-shaped casing ofelectrical conductive material and a tubular spacer of insulatingmaterial breaking the continuity of the casing; an inductance .coilwithin said housing; an annular band rotatably contained Within thecasing; and a series of blocks on the band, said inductance coil beingcarried by the said blocks.

2. A loop antenna for direction finding radio systems comprising alooped housing having a unitary tubular, ring-shaped casing ofelectrical conductive material and a tubular spacer of insulatingmaterial breaking the continuity of the casing; an inductance coilwithin said housing; an annular band rotatably contained within thehousing; and a series of blocks on the band carrying said inductance.coil, said blocks each being provided with spaced-apart openingstherethrough for the reception of strands of the inductance coil.

3. A loop antenna for direction finding radio systems comprising alooped housing having a unitary tubular, ring-shaped casing ofelectrical conductive material and a tubular spacer of insulatingmaterial breaking the continuity of the casing; an inductance coilwithin said housing; an annular band rotatably contained within thehousing; and a series of blocks on the band carrying said inductancecoil, each of said blocks comprising a plurality of sections, thestrands of the inductance coil being divided and disposed between thesections of said blocks.

4. A loop antenna for direction finding radio systems comprising alooped housing having a unitary tubular, ring-shaped casing ofelectrical conductive material and a tubular spacer of insulatingmaterial breaking the continuity of the casing; an inductance coilwithin said housing; an annular band rotatably contained within thehousing; and a series of spaced-apart blocks on the band carrying saidinductance coil, said annular band having a width less than the crosssectional diameter of the said casing whereby to' cause the annularedges of said band to engage the inner annular face of the casing.

5. A loop antenna for direction finding radio systems comprising alooped housing having a unitary tubular, ring-shaped casing ofelectrical conductive material and a tubular spacer of insulatingmaterial breaking the continuity of the casing; an inductance coilwithin said housing; an annular band rotatably contained within thehousing; a series of sectional blocks on the band carrying saidinductance coil; and clips securing together the sections of the blocksand the blocks to said band.

6. A loop antenna for direction finding radio systems comprising alooped housing having a unitary tubular, ring-shaped casing ofelectrical conductive material and a tubular spacer of insulatingmaterial breaking the continuity of the casing; an inductance coilwithin said housing; an annular band rotatably contained within thehousing; a series of sectional blocks on the band carrying saidinductance coil; and clips securing together the sections of the blocksand the blocks to said band, said inductance coil having parts thereofbetween the several sections of the series of blocks.

7. In an antenna of the character described having a tubular housing inthe form of a loop; a continuous annular band, flat in transverse crosssection, disposed within the housing with the edges thereof in linecontact with the inner face of the housing; a plurality of sectionalblocks mounted on one side of the band and extending radially outwardlyfrom the band; an inductance coil comprising a continuous conductorlooped upon the sections of said blocks with part of the loop betweensaid sections; and common means for attaching together the sections ofsaid blocks and the band.

8. In an antenna of the character described having a tubular housing inthe form of a loop; a continuous annular band, fiat in transverse crosssection, slidably disposed within the housing with the edges thereof inline contact with the inner face of the housing; a plurality ofsectional insulating blocks mounted on one side of the band andextending outwardly from the latter; and an inductance coil comprising acontinuous conductor looped upon the sections of said blocks with partof the loop between said sections.

9. In anantenna of the character described having a tubular housing inthe form of a loop; a continuous annular band, flat in transverse crosssection, slidably disposed within the housing with the edges thereof inline contact with the inner face of the housing; a plurality ofsectional insulating blocks mounted on one side of the band andextending outwardly from the latter; and an inductance coil comprising acontinuous conductor looped upon the sections of said blocks with partof the loop between said sections, the width of said band beingappreciably less than the inside diameter of the tubular housing, saidsectional blocks being on the outer-most side of said band.

HOWARD K. MORGAN.

